feat: add keybind status bar widget

This widget will show the state of the leader key sequence being
processed.

src/config.zig

@@ -18,6 +18,6 @@ indent_size: usize = 4,
 tab_width: usize = 8,
 
 top_bar: []const u8 = "",
-bottom_bar: []const u8 = "mode file log selection diagnostics linenumber",
+bottom_bar: []const u8 = "mode file log selection diagnostics keybind linenumber",
 
 lsp_request_timeout: usize = 10,

src/tui/status/keybindstate.zig

@@ -0,0 +1,43 @@
+const std = @import("std");
+
+const EventHandler = @import("EventHandler");
+const Plane = @import("renderer").Plane;
+const keybind = @import("keybind");
+
+const Widget = @import("../Widget.zig");
+
+allocator: std.mem.Allocator,
+plane: Plane,
+
+const Self = @This();
+
+pub fn create(allocator: std.mem.Allocator, parent: Plane, _: ?EventHandler) @import("widget.zig").CreateError!Widget {
+    const self: *Self = try allocator.create(Self);
+    self.* = .{
+        .allocator = allocator,
+        .plane = try Plane.init(&(Widget.Box{}).opts(@typeName(Self)), parent),
+    };
+    return Widget.to(self);
+}
+
+pub fn deinit(self: *Self, allocator: std.mem.Allocator) void {
+    self.plane.deinit();
+    allocator.destroy(self);
+}
+
+pub fn layout(_: *Self) Widget.Layout {
+    var buf: [256]u8 = undefined;
+    var fbs = std.io.fixedBufferStream(&buf);
+    const writer = fbs.writer();
+    writer.print("{}", .{keybind.current_key_event_sequence_fmt()}) catch {};
+    const len = fbs.getWritten().len;
+    return .{ .static = if (len > 0) len + 2 else 0 };
+}
+
+pub fn render(self: *Self, theme: *const Widget.Theme) bool {
+    self.plane.set_base_style(theme.statusbar);
+    self.plane.erase();
+    self.plane.home();
+    _ = self.plane.print(" {} ", .{keybind.current_key_event_sequence_fmt()}) catch {};
+    return false;
+}

src/tui/status/widget.zig

@@ -17,6 +17,7 @@ const widgets = std.static_string_map.StaticStringMap(CreateFunction).initCompti
     .{ "expander", @import("blank.zig").Create(.dynamic) },
     .{ "spacer", @import("blank.zig").Create(.{ .static = 1 }) },
     .{ "clock", @import("clock.zig").create },
+    .{ "keybind", @import("keybindstate.zig").create },
 });
 pub const CreateError = error{ OutOfMemory, Exit };
 pub const CreateFunction = *const fn (allocator: std.mem.Allocator, parent: Plane, event_handler: ?EventHandler) CreateError!Widget;